1. Field of the Invention
The present invention generally relates to communication systems. More particularly, the invention generally relates to wireless local area networks (WLAN) and more particularly still to a simplified method for CCMP mode encryption in a WLAN operating under the IEEE 802.11 standard.
2. Background Information
Initially, computers were most often used in a standalone manner. It is now commonplace for computers and other types of electronic devices to communicate with each other over networks. The ability for computers to communicate with one another has lead to the creation of small networks comprising two or three computers as well as vast networks comprising hundreds or even thousands of computers. Networks can be set up to provide a wide assortment of capabilities. For example, networked computers can be established to permit each computer to share a centralized mass storage device or printer. Further, networks enable electronic mail and numerous other types of services. Traditionally, networks have been established in a wired configuration in which each entity on the network has a direct physical electrical connection to the network. More recently, advances in wireless technology have made it possible for network devices to communicate with other devices via radio frequency (RF) or other types of wireless media.
Wireless networks are defined in various standards. The IEEE 802.11 standard, for example, permits a wireless local area network (WLAN) to be set up in a business or residence. In one form, the WLAN is a basic service set in which two or more stations communicate directly with each other, e.g. by radio frequency signals. In a more common configuration, one or more “access points” are set up at predetermined locations and are connected via cables to servers and other types of network equipment. Each access point also has a wireless radio capability to permit wireless communications with nearby wireless-enabled stations such as desktop computers, notebooks, handheld devices, and the like. Each access point has a certain range and a wireless-enabled device must be within that range for effective communications to occur. Through the access points, the wireless-enabled devices gain access to the network for data and file transfers, email, etc. The access points and wireless enabled stations have transmitters and receivers to perform the wireless communications.
Wireless transmission of data creates a number of challenges. It presents the opportunity for unauthorized reception of data transmitted from legitimate network stations and unauthorized transmission of data to legitimate network stations. For example, in a fragmentation attack an unauthorized station may receive one or more authentic data transmissions, possibly modify portions or reorder the fragments and then retransmit them. Serious damage can occur if an authorized station receives such unauthorized transmissions and performs various acts based on them. Such events may occur accidentally or intentionally. The IEEE 802.11i standard has been established to provide systems for controlling access to WLANs and providing security for transmitted data.